The Spaniard is already assured of ending the year as world No 1 having won a 10th French Open title and the US Open.

But despite 75 singles titles in his illustrious career, including 16 Grand Slams and 30 Masters events, he has yet to triumph at the ATP Finals and has now pulled out of the season-ending tournament for the sixth time in 13 attempts due to injury.

You're 31 years of age - do you want to take this risk?

Sky Sports' analyst Rusedski could not understand why the 31-year-old "took risks" in order to play in London, but does feel he will be back winning Grand Slams next year.

"He made a commitment to this event, he said 'I'm going to try and play one match'. I think before this match, had it not been the ATP Finals, I don't even think he would have played," said former US Open finalist, Rusedski.

"So in Paris the injury was already pretty bad. Maybe he took some painkillers or got an injection and said, 'I'm going to play one match and that's it'. In retrospect you wonder whether that was the right decision.

"He knows what the treatments have to be to get this problem resolved, but at the end of the day you think to yourself, 'you're 31 years of age - do you want to take this risk?'

"He has accomplished everything in the sport apart from winning this event and then you see him grimacing like that. You wonder how much will this set him back for 2018? That's where Roger Federer looks at the crystal ball that little bit better."

And when asked my host Marcus Buckland whether or not he thinks Nadal can come back from this setback, Rusedski added: "Yes, I think he's going to win majors next year, but the question is will he be ready for the Australian Open? That's something I don't know.

"I think Rafa's still got a lot more majors and a lot more great tennis ahead of him."

The season-ending extravaganza ATP Finals ends another memorable year which will be covered via our website www.skysports.com/tennis with live blogs, reports, reaction and expert analysis as the season reaches its climax.

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